Bluetooth audio through AirPods (CM4)

[StonedEdge]

Hi all,

I've managed to get audio working through my AirPods via the inbuilt bluetooth module but I am struggling to get both my sound card and audio working out of bluetooth simultaneously. I'm currently not using pulseaudio (only ALSA, via BlueAlsa - not using pulseaudio as I find it slows down RetroPie significantly).

My current /etc/asound.conf file looks like this:

# use samplerate to resample as speexdsp resample is bad
defaults.pcm.rate_converter "samplerate"

pcm.!default {
    type asym
    playback.pcm "playback"
    capture.pcm "capture"
}

pcm.playback {
    type plug
    slave.pcm "dmixed"
}

pcm.capture {
    type plug
    slave.pcm "array"
}

pcm.dmixed {
    type dmix
    slave.pcm "hw:seeed2micvoicec"
    ipc_key 555555
}

pcm.array {
    type dsnoop
    slave {
        pcm "hw:seeed2micvoicec"
        channels 2
    }
    ipc_key 666666
}

My current .asoundrc file looks like this:

pcm.!default {
  type asym
  playback.pcm {
    type plug
    slave.pcm "output"
  }
  capture.pcm {
    type plug
    slave.pcm "input"
  }
}

pcm.output {
  type hw
  card 0
}

ctl.!default {
  type hw
  card 0
}

pcm.!default {
        type plug
        slave {
                pcm {
                        type bluealsa
                        device BC:B8:63:45:65:C0
                        profile "a2dp"
                }
        }
        hint {
                show on
                description "Apple AirPods"
        }
}
ctl.!default {
        type bluealsa
}

Is there any way to get both audio playing out of both devices, ideally whereby one audio device switches off (i.e the internal audio card) when the bluetooth speakers are connected and vice versa? I think I need to shift the pcm.!default & ctl.!default contents somewhere else, but this doesn't seem to work for both audio cards (i.e sound only comes out of the bluetooth speaker with the above configurations) at the moment.

The other problem I'm having at the moment is with latency via blue alsa. The audio is definitely half a millisecond or so behind the video which makes it basically unusable in it's current state...

Cheers.